Observations and prediction of phenological trends in two Italian phenological gardens

In most climates, following dormancy, the annual timing of spring phenological events is mainly driven by temperature. Variations in phenological stages are therefore considered a valuable source of information for investigating the possible impact of climate variability and change on plant species. Recent European studies indicating changes in phenological stages in plant and animal species provide evidence that ecosystems are responding to climate change. However, most information is still scarce and limited to temperate and cold ecosystems of northern latitude. To investigate the inter-annual variability in the beginning of growing season and flowering phases in Italy, phenological data-sets (1986-2007) from two sites of the Italian Phenological Garden network were analyzed. The sites were Oristano, Sardinia, Italy (39° 53' N, 8° 37' E, 11 m above sea level) and S. Pietro Capofiume, Emilia Romagna, Italy (44° 39' N, 11° 37' E, 10 m above sea level). The gardens were established in the early 1980s following the guidelines of the International Phenological Gardens in Europe (IPG). Phenological observations were taken on Mediterranean forest species and shrubs in Sardinia, Italy and on several forest species typical of higher latitude in Emilia Romagna, Italy. Data analysis was conducted to describe the phenological behavior of native and non-native species, and to assess their sensitivity to temperature. Only one species showed earlier flowering and another had earlier bud break. In both cases, there was some evidence that the change was related to higher temperatures prior to the phenological phase. There was no trend towards earlier bud break or flowering for the other non-native or native species.